TEHRAN, Iran (CNN) -- Officials say two men in Iran have been stoned to death for adultery and murder, while another escaped death by digging his way out of the hole where he was buried to face a similar fate, according to media reports.

The sentences follow sharp criticism by human rights groups of Iran's use of such punishments.

Judiciary spokesman Alireza Jamshidi on Tuesday told reporters about the stonings, which took place in the northeastern city of Mashhad about 20 days ago, the reports said.

According to the Mashhad prosecutor, the men committed various crimes, including adultery and murder, Jamshidi said.

In the practice, the men are buried up to their chests and people pelt them with stones until they die.

A third was supposed to have been stoned to death. However, he freed himself by climbing out of the stone hole. He still awaits punishment.

"Stoning is a horrific practice, designed to increase the suffering of those facing execution, and it has no place in the modern world," Amnesty International said last year.

Jamshidi said Iran's judiciary chief, Ayatollah Heshemi Shahroudi, had made recommendations that would ban the practice and said that a measure has been introduced in Parliament to stop the punishment.

But "until this measure is approved and becomes law, the judges have the independence not to pay heed to the recommendations of the Judiciary chief," Jamshidi said.

Amnesty said in a report last year that Iran's penal code allows execution by stoning as the penalty for adultery. The group said the law calls for stones "large enough to cause pain, but not so large as to kill the victim immediately."

In August, Amnesty International issued a statement welcoming an announcement that stoning had been suspended and several women had their sentences commuted.

In that announcement, the group said at least one stoning execution was carried out in 2007 in Qazvin province and a woman and a man were known to have been stoned to death in Mashhad in May 2006.

"The majority of those sentenced to death by stoning are women. Women are not treated equally with men under the law and by courts, and they are also particularly vulnerable to unfair trials because their higher illiteracy rate makes them more likely to sign confessions to crimes they did not commit," Amnesty said.